Wallace c



UNITED STATES PATENT OFFICE.

WALLACE C. ANDREWVS, OF NEl/V YORK, N. Y.

VULCANIZING WOOD.

SPECIFICATION forming part of Letters Patent No. 430,055, dated June 10, 1890.

Application filed 'April 28, 1890. Serial No. 34:9,825- (N0 specimens.)

To all whom it may concern:

Be it known that I, WALLAcE C. ANDREWS, a citizen of the United States of America, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Preserving W'ood; and I do hereby declare the following to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to wood-preserving.

The object is in a rational and efficient man ner to treat wood to preserve it from decay and at the same time to improve it in many respects as regards durability, strength, color, and capability of finish.

The invention consists in vulcanizing wood in the manner more fully hereinafter described.

Heretofore it has been attempted to vulcanize wood by subjecting it to a boiling temperature and then applying additional heat with pressure of an aeriform fluid. It has also been attempted to vulcanize wood by application of heat and aeriform pressure simultaneously. sapsuch as resinous or other matter-will boil before the pressure is applied to keep it in the body of the wood. In the second case, in addition to the difiiculties of conducting highly-heated air through pumps and pipes under pressure, the great heat at which the aeriform fluid must be introduced in order to be effective is apt to cause the contained sap of the wood to boil and to exude before the pressure will rise to a sufficient point to keep it in; or, as expressed, it will be apt to cause the wood to fry. The point to be achieved is by heat and pressure to so treat the wood that the contained sap will be solidified in the cells of the wood and not exude, and will undergo such chemical change that it will act as a preservative of the wood. To accomplish this successfully, I place the wood first under pressure and then apply the requisite heat. This is the invention, and, as will be obvious, it may be carried into effect in various ways.

In the first case the contained As an illustration of one specific mode of procedure, the following will suffice: Green lumber in a car or otherwise is introduced into a suitable drying-chamber, such as a cylinder provided with means for heating it, as by steam-pipes at the ends and coiling along the sides within. The drying-chamber is then tightly closed, and any suitable dry aeriforni fluid, preferably atmospheric air, at ordinary temperature is forcibly introduced until the contents of the receptacle are under high.

pressure. Steam at a high heat-say at a pressure of two hundred to three hundred pounds, more or less, so that a heat of, say,

300 to 400 Fahrenheit, more or less, will be obtained-is then passed into the coil. The lumber is left in the chamber for from four to twelve hours, according to its condition when introduced and according to the kind of lumber under treatment. The more dense the lumber and the less gummy it is the less time it will take to vulcanize it. The higher the heat and the longer the time of subjection the deeper will be the color of the wood when it comes out. Whatever aeriform fluid is employed, the same is thoroughly dried by any suitable means before it is introduced into the cylinder.

Any suitable apparatus in the art may be employed for carrying my invention into effect.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

The method of vulcanizing wood, which consists in first placing the same in a closed receptacle under high pressure of an aeriform fiuid at ordinary temperature or without heat sufficient to boil the sap, and then while retaining pressure highly heating the contents, substantially as described.

In testimony whereof I afiiX my signature in presence of two witnesses.

WVALLACE C. ANDREI/VS.

Witnesses:

R. G. DYRENFORTH, LEWIS Goon. 

